### TODO:
# point, line, plane, circle, sphere, polygon, etc.
#   closest point
#   intersection
#   length / volume / area etc.
#
# convex hull
# voroni diagram
# delaunay triangulation
# closest pair of points

# a=(ax,ay,az) cross b=(bx,by,bz):
#  (ay bz - az by, az bx - ax bz, ax by - ay bx)
#  np.cross

import numpy as np

class Point(object):
	def __init__(self,coords):
		self.p=np.array(coords)
		assert(len(self.p.shape)==1)

class Line(object):
	def __init__(self,a,b,)